MISTY, Crawford, Texas: I am currently studying psychology. I have never understood how someone could do things so horrific and not be mentally ill. There has to be an illness that would cause people to do such things. I do not believe normal healthy beings could possibly behave in this way. Especially with this case -- she did not even show emotion once she knew she was caught.
KNOLL: Thanks for your question, Misty. You made me remember when I was a medical student, watching the grisly details of the Jeffrey Dahmer case unfold. I thought the same thing to myself: Come on -- body parts in his house, eating human biceps? How can this guy not be seriously mentally ill?!
Later, I would do my forensic specialty training with a forensic psychiatrist who actually worked on the Dahmer case. I came to learn that it is always a dangerous thing to conclude serious mental illness based solely on the nature of the crime. In other words, one should be very careful about assuming someone must have been very mentally ill because they committed a crime that was horrific or bizarre, etc. This is because of the fact that relatively "normal" people can and do commit such acts - as unnerving as this may seem.
That said, please also see my previous response to a question about the nature of "mental illness," and who is doing the defining of it. Recall the the law usually only regards "serious" mental diseases or defects as qualifying for potential mental health defenses. Why? Because lesser entities that we may lable "disorders" are not regarded as significantly impairing a persons judgment or perception of reality. I do agree with you that "healthy" persons do behave this way, but "health" is a continuum, and while a person may not have what we would consider healthy family relationships and ways of living, they still may be healthy enough to function in society, make choices and exercise judgment that is not significantly impaired.
Incidentally, back to Dahmer for a moment: some excellent forensic psychiatrists have been re-examing his case and wondering about whether he may have suffered from a particular kind of neurodevelopmental deficit. [i], [ii] These investigators have described an association between autism spectrum disorders and a subgroup of serial murders, and propose that Dahmer may have suffered from an illness known as Asperger's disorder. Along these lines, it is interesting to note that after exhaustive interviews with Dahmer, legendary FBI profiler Robert Ressler (coined the term serial killer) was impressed by the "peculiar" nature of Dahmer's presentation. [iii] Of course, such a disorder would be unlikely to rise to the level required by the law to serve as a mental health defense, but from a purely scientific standpoint, this seems fascinating.
[i] Silva J, Ferrari M, Leong G. The case of Jeffrey Dahmer: Sexual homicide from a neuropsychiatric developmental perspective. J Forensic Sci 2002 47(6):1347-59. [ii] Silva J., Leong G., Ferrari M. A neuropsychiatric developmental model of serial homicidal behavior. Behav Sci Law 2004 22(6):787-99. [iii] Ressler R. How To Interview A Cannibal. In: Profilers: Leading Investigators Take You Inside the Criminal Mind (J. Campbell and D. Denevi, Eds.) Prometheus Books: Amherst, New York, 2004.